From the title, “the cold equations,” you learn that the author
a. does not like the idea of space travel
b. thinks that spaceships are uncomfortable
c. is not very good at understanding science
d. thinks mathematical equations are unfeeling

D. thinks mathematical equations are unfeeling

Explanation:

YOu can read the Title Cold Ecuations, and have a feeling that the author thinks that mathematical equations are unfeeling, because of the use of the world cold, as a reference to when people refer to other people as cold, when those people do not show sentiments and aren´t warm and welcoming.

the following key ideas correctly express the key sentence.

restate key idea: most people can learn to swim in ten short lessons.

restate key idea: the majority of water-accident victims require mouth-to-mouth breathing.

restate key idea: an empty, tightly closed gallon jug will support a tired swimmer.  

restate key idea: first aid is to prevent accidents as well as assist in rescue.

explanation: the key idea needs to have the same topic as the key sentence (drowning and safety).